I just learnt the difference, an em-dash is as long as an m and used for other things than the shorter en-dash (as long as an n).
Em-dashes are more common in literature, which a lot of AI is trained on, rather than online speak where it’s annoying and difficult to notice the difference between - and — (and not to be confused with –).
TACO?
https://www.youtube.com/watch?v=nUwTnJ8yFXY